用户编辑帖子更新数据库

I am trying to update my database with a post that a user has edited in a forum. The whole edit form is functioning except for: when they click edit, the form submits and goes to the main forum page, but the database and the post don't change.

My save edit code is this:

 #data preparation for the query  
$id=intval($_POST['id']);   
$a_id=intval($_POST['a_id']); 
$question_id=intval($_POST['question_id']);
foreach ($_POST as $key => $value)  
$_POST[$key] =
mysql_real_escape_string($value); 


 $sql = "UPDATE $tbl_name SET
a_answer='$_POST[a_answer]' WHERE
a_id='$a_id' AND
question_id='$question_id'";

 if (!mysql_query($sql)) {   
die('Error: ' . mysql_error());   }  
mysql_close;   header ("location:
main_forum.php"); 

 ?>

My code for the edit page is this:

#data preparation for the query 
$id=intval($_GET['id']);  
$a_id=intval($_GET['a_id']);
$question_id=intval($_GET['question_id']);

# selects title and description fields from database
$sql = "SELECT a_answer FROM $tbl_name WHERE a_id='$a_id' AND question_id='$question_id'";
$result=mysql_query($sql);
$rows=mysql_fetch_array($result);  

?> 

And the HTML

<h3>Edit</h3>
<form action="save_edit.php" method="get" name="myForm" />
<center>
  <table>
    <tr>
      <td valign="top">
        <b>Answer</b>
      </td>
      <td>
        <textarea cols="80%" rows="10" name="a_answer">
          <?php echo htmlspecialchars($rows['a_answer']); ?>
        </textarea>
      </td>
    </tr>
    <tr>
      <td colspan="3">
        <input name="a_id" type="hidden" value="&lt;? echo $rows['a_id']; ?&gt;">
          <input name="question_id" type="hidden" value="&lt;? echo $rows['question_id']; ?&gt;">
            <input type="submit" name="Submit" value="edit post">
              <?php mysql_close(); ?>
            </input>
          </input>
        </input>
      </td>
    </tr>
  </table>
</center>

You are mixing up get and post. In your form you use method="get" while you use $_POST in the processing page. Change your form to method="post":

<form action="save_edit.php" method="post" name="myForm">

PS. You shouldn't close an opening tag with />.